A Vaccine for Children Has Cut Cases Among Youngsters, but There's No Vaccine for Adults
By Denise Mann
WebMD Health News
Reviewed by Laura J. Martin, MD
Aug. 11, 2011 -- Hib disease may be on the rise among adults, according to a new study.
The study published in Emerging Infectious Diseases looked at Utah residents.
Spread by direct contact or via droplets from coughing or sneezing, Hib disease has decreased dramatically in children due to the advent of a Hib vaccine in 1992. There is no such vaccine available for adults.
Now researchers report an uptick in invasive Hib disease seen among adults in Utah from 1998 to 2008. Reasons for the increase may include changes in the organism, greater numbers of high-risk people, or waning immunity to the bug.
Overall, there were 121 cases of Hib disease reported to the Utah Department of Health during the study period. The risk of invasive Hib disease was higher among people aged 65 and older, compared to younger people. Fully 51% of invasive disease occurred among adults in this age bracket, and two-thirds of Hib-related deaths occurred among those aged 65 and older, the study showed. The increase was largely spurred by nontypeable Hib strains and H. influenzae serotype f (Hif).
While the new study only tracked Hib in Utah, other reports have documented parallel increases in Spain, Illinois, and Alaska.
"These data have implications for targeted adult H. influenzae vaccine development," conclude researchers who were led by Matthew P. Rubach, MD, an infectious disease specialist at Duke University Medical Center in Durham, N.C.